Posted
by
samzenpus
on Monday October 03, 2011 @09:55AM
from the where-the-sidewalk-ends dept.

MrSeb writes "The largest astronomical installation in the world is now operational. ALMA, or the Atacama Large Millimeter Array, is a vast radio telescope made out of 66 12- and 7-meter dish antennae situated 5,000m above sea level, in Chile. Its purpose is to seek out new life and new civilizations and to boldly go where no telescope has gone before. But no, seriously: its job is to peer into the past and investigate ancient stars and nebulae, peer at exoplanets that might support human (or alien) life, and hopefully learn more about interstellar creation and destruction. For now only 20 out of 66 antennae are in place, but when it is complete — late next year — it will have a resolving power far greater than Hubble, according to the European Space Observatory (ESO) that operates ALMA."

As an astrophysicist who's highly interested in using ALMA, I can say that this short description undersells the capabilities of ALMA. While the image resolution is going to be greater than that of Hubble, ALMA will also be observing wavelength ranges previously unobserved from the ground. While space based instruments such as Herschel have observed some of these ranges in the past, these observations don't even come close to the spatial resolution of ALMA.

That undersells it. It can form a 1.21 gigapixel image of the sky at each frequency channel: and if it's like other radio telescopes, it will have thousands of channels. The raw data coming in the front end, before it's reduced down to an image, is even heftier.

Ummm. you underestimate out arrogance and lack of perception of the outside world's opinion.

We are sick of everyone else not using the imperial system (who's creators even dropped it!)Not of people complaining we use a non-SI system. We could care less about what everyone else thinks. That's why we have n

I think one of the problems with modern aastronomy is that they often cannot help BUT see that church down the street.

I think it might have something to do with the las-vegas style neon lights, dancing searchlight beams, the well illuminated "second coming landing pad" which tries earnestly to coax jesus to put his foot down there, or the fact that it is owned and operated by Landover Ministries.

But then again, I am one of those heathen "unsaved" that only makes 30k/year, and am excluded from even bronze level membership, so maybe I hold a little bit of jealous bias when I say that it would be a good thing to regulalrly cut power to that light pollution retching eyesore so that astronomers might get some REAL insight into the nature of the heavens, but I don't think it would be a whole lot of it.

My wife operates a 3.5 meter telescope, fortunately a ridge blocks most of the town below, but not the air force base next door, for some reason they like to keep the lights on for their runways. She has some strong opinions about city light and Las Vegas. The funny thing is: she was invited as a guest to a convention in Vegas and we went! It was kind of amusing watching her cringe and bitch.

If my interpretation of the bible is correct, Jesus may well appear at Landover Ministries, and utterly lay was

Lateral resolution is about 0.61*wavelength / NumericalAperture. The smaller this number , the smaller the distance at which two distinct points of light can be resolved.

It is entirely meaningful to compare the spatial resolution of two devices observing in different wavelengths. Shorter wavelengths have a lower theoretical limit , sure. But even if Hubble observes at shorter wavelengths, the ALMA has a big fucking numerical aperture. Which makes its resolution better.

I am sure you optics whizzes understand that basic lateral resolution is about 0.61*wavelength / NumericalAperture. The smaller this number , the smaller the distance at which two distinct points of light can be resolved.

It is entirely meaningful to compare the spatial resolution of two devices observing in different wavelengths. Shorter wavelengths have a lower theoretical limit , sure. But even if Hubble observes at shorter wavelengths, the ALMA has a big fucking numerical aperture. Which makes its resolu

What definitions are being used to declare this the "largest astronomical installation in the world" as opposed to the VLBA [wikipedia.org]? The VLBA claims to be the "world's largest, full-time astronomical instrument." [nrao.edu] I can't seem to find exact info on ALMA's baseline, but i doubt it exceeds 8611 km.

It looks like a clever acronym of English words that makes a Spanish word, giving it a pleasant double meaning. A backronym is when you name something, and come up with something for it to stand for later. AMBER Alert contains a backronym. The original name was after Amber Hagerman, so it was Amber Alert. They made a backronym to make it extra kewl.

Yup. Think of it like you're an ant on the surface of an expanding balloon. There is no "center" to the _surface_ of the balloon. Every point on the balloon is moving away from every other point on the balloon, and the further apart two points are, the faster they are moving apart. The "surface" of the universe is 3D though. (Read Flatland [gutenberg.org], then Sphereland [amazon.com].)

Even if everything is moving away from everything else, there should be some line you could draw that says everything on this side of the line is moving away from everything on that side. Do that for all three dimensions and the lines intersect at the center. Dump a bucket of marbles on the floor in a 2D Big Bang. They would be ALL moving away from SOME single thing. Even if we glue the marbles to a rubber sheet and pull it in all dir

Nope. There is no center, or rather, every point appears to be equivalently central. You can't mark the "center" of the surface of a sphere; that's meaningless. Sure, you can mark the center of the sphere, but the center of the sphere is not a part of the surface of the sphere. If the universe is the surface, then the center is not a part of the universe. From within the universe, the center does not exist. And sure, you could mark any point on the sphere and call it "the center", and every other point on t